(a) Field of the Invention
The present invention relates to a non-oriented electrical steel sheet composition, a manufacturing method of a non-oriented electrical steel sheet product, and a non-oriented electrical steel sheet product.
(b) Description of the Related Art
A non-oriented electrical steel sheet is a steel sheet of which a magnetic property thereof is uniform in all directions on a rolling plate, and is widely used in a motor, an iron core of an electric generator, an electric motor, a small transformer, and the like.
The non-oriented electrical steel sheet may be divided into two types such as one in which stress-removing annealing (SRA) for improving the magnetic property after punching work should be practiced and the other in which the SRA is omitted if a cost loss is larger than the effect of the magnetic property by the SRA
Also, the non-oriented electrical steel sheet is used in demanding markets of driving motors, home appliances, and large motors to be separated.
A forming of the insulating film is a procedure which belongs to a finishing process for manufacturing a product, and requires stickiness resistance such that steel sheets of iron cores are not adhered to each other after the SRA which recovers the magnetic property by removing the processing stress of the steel sheet and the continuous punching workability inhibiting abrasion of a mold, and surface adherence and the like, upon preparing iron cores by laminating many materials after the punching work in a predetermined shape, in addition to electrical properties inhibiting occurrence of an eddy current.
In addition to said basic characteristics, excellent application workability of a coating solution, solution stability usable for a long period after the combination, and the like are also required.
Meanwhile, a main purpose of a non-oriented insulating film resides in inter-layer insulation between iron sheets to be laminated. However, as the use of small electric motors is increased, film performance advantageous to workability, weldability, and corrosion resistance, as well as an insulating property, is evaluated as a major physical property, and recently an electrical steel sheet having excellent surface quality has been required as the surface quality of the steel sheet also has an effect on the use characteristics.
Also, the non-oriented electrical steel sheet is currently riding a wave of high-end usage by the development of high efficiency motors to keep pace with government's low-carbon policy, and as it proceeds to the high-end usage, the surface of the electrical sheet requires high functionality (high insulating property, high heat resistance, and high corrosion resistance).
In particular, an excellent insulating property between the layers of non-oriented electrical steel sheets, by which the performance of motor can be maximized by minimizing eddy current loss, is an essential factor. In order to secure an excellent insulating property for the non-oriented electrical steel sheet, the method of increasing a coating thickness thereof is the most common method. However, if the coating thickness is increased, there is a disadvantage that the properties such as weldability, heat resistance, adherence before/after SRA, stacking factor, and the like, are deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.